There are three generations of Toyota Tundra pickups, and there's a big difference between the first- and second-generation trucks. The original Tundra was a smaller pickup--sometimes dubbed a 3/4-sizer, when compared with the Dodge Ram, Ford F-150, Chevy Silverado, and GMC Sierra of the day. In the 2007 model year, the second-generation Tundra grew up and out; its added weight and capability makes its biggest 5.7-liter engine more of a must-have. The third-generation truck has been mostly a mechanical carryover--so the same recommendation holds true.